I wouldn't go to a shop I just did mine along with the 4th apply it's very easy if you do your research. Somewhere on here there is a link to boxwrench.com where they show dis-assembly a reassembly of the servo housing. I would just google search boxwrench.com and click on videos then select 4l60e videos and watch it about 20 times then go for it. That's what I did anyway. just a heads up leave the 4th apply INSIDE the cover during installation otherwise you'll tear up the seal and lose over-drive.
I thought the install was cake, and I wouldn't consider myself mechanically inclined. I mean I've replaced alternators and starters and such but nothing major. The main thing is making sure to get the snap ring all the way in which is easy just poke it with a screwdriver all the way around the ring. Heck, I'd do it for you for free if you lived anywhere near oklahoma. It literally takes less than an hour once everything is cooled off.
PS most shops don't want to mess with them because they don't know anything about the condition of your transmission and if it goes out and they were the last ones to have it apart it's a can of worms they'd rather not open. That's why they charge so much.